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    SubjectRe: [PATCH v2 11/11] sched: replace capacity by activity
    On 29 May 2014 15:55, Peter Zijlstra <peterz@infradead.org> wrote:
    > On Fri, May 23, 2014 at 05:53:05PM +0200, Vincent Guittot wrote:
    >> The scheduler tries to compute how many tasks a group of CPUs can handle by
    >> assuming that a task's load is SCHED_LOAD_SCALE and a CPU capacity is
    >> SCHED_POWER_SCALE.
    >> We can now have a better idea of the utilization of a group fo CPUs thanks to
    >> group_actitvity and deduct how many capacity is still available.
    >>
    >> Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
    >> ---
    >
    > Right, so as Preeti already mentioned, this wrecks SMT. It also seems to
    > loose the aggressive spread, where we want to run 1 task on each 'core'
    > before we start 'balancing'.
    >
    > So I think we should be able to fix this by setting PREFER_SIBLING on
    > the SMT domain, that way we'll get single tasks running on each SMT
    > domain before filling them up until capacity.
    >
    > Now, its been a while since I looked at PREFER_SIBLING, and I've not yet
    > looked at what your patch does to it, but it seems to me that that is
    > the first direction we should look for an answer to this.

    OK, i'm going to look more deeply in PREFER_SIBLING too


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